To calculate how much liquid remains for a particular item, WISK uses a combination of a few factors:

Product's

*full weight*— weight of the item and its contents when fullProduct's

*tare weight*— weight of the empty item excluding the liquid inside*Liquid's density*— necessary to convert weight into volume (liquor categories in WISK already have this assigned)*Spout weight*— to account for the added weight of various spout types

Here is a simplified outline of the calculation process:

Get the weight of the partially filled item from the Bluetooth scale and subtract any added weight from the spouts

Check to see what the item's full weight is

Check to see what the item's empty weight is — if we don't have the empty item weight, we can use the item's volume and the liquid's density to determine this

Compare the full/empty item weights to the partial weight in (1) to determine the proportion of the item's contents that remain